Apparatus for dry cleaning exposed films

Abstract

An apparatus for cleaning exposed film includes a dry cleaning unit including at least a first dry cleaning station comprising an ionization unit having an electrostatic discharge device and means for removing discharged dust particles from the film. A roller driven by a drive motor draws the film from an unwinding reel through the dry cleaning unit. A film take-up reel driven by a controlled drive motor is disposed downstream of the driven roller. The controlled drive motor is controlled so that a tensile force acting on the film remains uniform as a diameter of the film winding on the film take-up reel varies. A satisfactory cleaning of the film is thus achieved, even when cleaning old and heavily-soiled films, together with a reliable take-up of the cleaned film without a danger of film breakage in the film cleaning apparatus.

What is claimed is: 
     
       1. An apparatus for cleaning exposed film, comprising: a dry cleaning unit including at least a first dry cleaning station comprising an ionization unit including an electrostatic discharge device and means for removing discharged dust particles from the film;   a drive motor;   a roller driven by the drive motor for drawing the film from an unwinding reel through the dry cleaning unit;   a controlled drive motor;   a film take-up reel driven by the controlled drive motor and disposed downstream of the driven roller; and   means for controlling the drive motor so that a tensile force acting on the film remains uniform as a diameter of the film winding on the film take-up reel varies.   
     
     
       2. The apparatus as defined in claim 1, wherein the driven roller comprises a capstan roller. 
     
     
       3. The apparatus as defined in claim 1, wherein the driven roller comprises a sprocket wheel. 
     
     
       4. The apparatus as defined in claim 1, wherein the dry cleaning unit further comprises a second dry cleaning station disposed downstream of the first dry cleaning station for removing dirt and dust particles from opposing surfaces of the film by at least one of adhesion and electrostatic attraction. 
     
     
       5. The apparatus as defined in claim 4, further comprising a limit switch disposed along the film strip prior to the second dry cleaning station for detecting a break in the film, said limit switch being coupled to the drive motor and the controlled drive motor for deactivating said motors in response to a break in the film. 
     
     
       6. The apparatus as defined in claim 4, further comprising a shunt roller disposed between the second dry cleaning station and the driven roller so that the film can be guided to bypass the second dry cleaning station. 
     
     
       7. The apparatus as defined in claim 1, further comprising first and second deflection rollers disposed, respectively, in front of and behind the driven roller for wrapping the film around a significant portion of a circumference of the driven roller. 
     
     
       8. The apparatus as defined in claim 1, wherein the film take-up reel and the unwinding reel are disposed in a common plane so that the film can be rewound directly between said reels while bypassing the dry cleaning unit. 
     
     
       9. The apparatus as defined in claim 1, further comprising a housing enclosing at least the dry cleaning unit, and an exhaust device communicating with the inside of the housing and having an upstream dust filter for dirt and dust particles brushed off in the first dry cleaning station. 
     
     
       10. The apparatus as defined in claim 9, further comprising a sensor for detecting a degree of soiling of the dust filter and a display coupled to the sensor for displaying the degree of soiling.